The invention relates to a hanging for a roller blind or window shade, which is provided at its lateral edges with guide elements for positive cooperation with lateral guide devices.
A roller blind hanging is known, which is provided on each of its lateral edges with a xe2x80x9chalf slide fastener,xe2x80x9d so that in cooperation with a guide groove, a welt effect is obtained. A significant disadvantage of such a guide system is that on rolling the blind up onto a winding roller the xe2x80x9chalf slide fasteners,xe2x80x9d acting as guide elements, are superimposed to form beads, which brings about a creasing of the hanging and leads to an increased space requirement around the winding roller.
Another known possibility for the lateral guidance of a roller blind hanging consists of the hanging being provided on its lateral edges with rivets or the like, but this also leads to the aforementioned disadvantages.
The problem solved by the invention is to so improve a hanging so that on rolling up there is no longer any bead formation or bulging as a result of the superimposed guide elements.
According to the invention this problem is solved by a hanging for a roller blind, which is provided on its lateral edges with guide elements for positive cooperation with lateral guide devices. The hanging is characterized in that the guide elements are formed by guide strips made from a flexible material. Each guide strip is fixed to facing end portions on the fixed hanging and the mutual spacing of the end portions of the guide strip in the fixed state is smaller than in a planar or stretched state of the guide strip, so that a guide area of the guide strip located between the fixed end portions and not connected to the hanging projects in convex manner from the hanging and can be positively received in a guide device.
Preferably the guide strips are rectangular and are positioned parallel to the lateral edges of the hanging.
The guide strips are appropriately located on an outer hanging surface during rolling up.
Preferably the mutual spacing of the end portions of the guide strips fixed to the hanging are so adapted to the diameter of a winding roller receiving the hanging that on rolling up the guide areas engage substantially flat on the hanging.
Preferably the guide strips are made from a plastic film, particularly an embossed polyester film. Preferably the guide strips are joined to the hanging by ultrasonic welding or bonding.
Alternatively a single, continuous guide strip is connected at intervals with the hanging, accompanied by the formation of projecting guide areas.
The invention also relates to a roller blind with a hanging and two lateral guide devices for receiving the guide strips. It is possible for each guide device to have a guide rail with an undercut-like guide groove with a narrowed guide portion for the passage of the hanging and a widened reception portion for receiving the guide strip or the guide areas projecting from the hanging.
The invention also relates to a method for the manufacture of the hanging, which is characterized by the following steps: providing a cylindrical or cylinder sector-shaped working template or stencil, whose diameter corresponds to the diameter of a winding roller used with the hanging, placing an area of a lateral edge of the hanging to be provided with a guide strip on the working template in accordance with the curvature thereof, placing a guide strip on the area of the lateral edge corresponding to the curvature thereof, placing a guide strip on the area of the lateral edge corresponding to the curvature thereof, joining facing end portions of the guide strip to the hanging, particularly by ultrasonic welding or bonding, so that a guide area of the guide strip located between the end portions connected to the hanging and not actually connected to the hanging projects in curved manner therefrom in the stretched state.